The specialty of obstetrics and gynecology can be divided into two parts. Obstetrics focuses on the care and treatment of women before their pregnancy, during the pregnancy, and after the child is born. Gynecology is concerned with the treatment of diseases and disorders of the female reproductive system. Because the areas overlap, the specialties are generally practiced together. Preventive measures and testing make up a large part of an OB/GYN's practice.

Obstetricians/gynecologists provide many different types of health services to women, from prenatal care to Pap tests to screening tests for sexually transmitted diseases to breast exams and birth control. With specialization, the OB/GYN's practice may focus on pregnant patients, cancer patients, or infertile patients.

When an examination and test indicate that a patient is pregnant, an OB/GYN sets up regular appointments with the patient throughout the pregnancy. These visits make up a crucial part of any woman's prenatal care, helping her learn about her pregnancy, nutrition and diet, and activities that could adversely affect the pregnancy. In addition, the patient is examined to see that the pregnancy is progressing normally. Later in the pregnancy, the frequency of visits increases, and they become important in determining a birthing strategy and any alternate plans. An OB/GYN will deliver the baby and care for the mother and child after the delivery.